In recent years, studies on an organic electroluminescence device which emits light when an electron injected from a cathode and a hole injected from an anode are recombined within an organic fluorescent substance sandwiched between both electrodes are actively made. This device is characterized by a low-profile, emission of high emission brightness at a low driving voltage and multicolor emission by selecting a fluorescent material, and receives attention. The studies on this device have been made by many research laboratories since C. W. Tang et al. of Kodak Company have shown that the organic electroluminescence device emits light at high brightness.
Earnest studies are made aimed at realizing full color display. As an emissive material, not only fluorescent materials but also phosphorescent materials are studied. Further, as for a charge transporting material, studies on a hole transporting material have been hitherto heavily made but recently, earnest studies on an electron transporting material are made (see, for example, Patent Documents 1 to 5).    Patent Document 1: Japanese Unexamined Patent Publication No. 5-331459 (scope of claims)    Patent Document 2: Japanese Unexamined Patent Publication No. 2000-119644 (p 17)    Patent Document 3: International Publication WO 00/03565 (scope of claims)    Patent Document 4: Japanese Unexamined Patent Publication No. 2003-115387 (scope of claims)    Patent Document 5: Japanese Unexamined Patent Publication No. 2003-123983 (scope of claims).